|Knothe, Gerhard - Gary|
|Dunn, Robert - Bob|
Submitted to: Oilseed Processing and Utilization World Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 10/10/1996
Publication Date: N/A
Technical Abstract: The use of intact fats and vegetable oils as diesel fuels causes severe engine problems in part because of the high viscosity of their component triglycerides. Remedies for this problem are microemulsification, transesterification, dilution, and pyrolysis. Currently, the formation of alkyl esters (AE), usually methyl esters (ME), is the technology of choice because their viscosities and engine performance are comparable to diesel fuel. Other advantages of AE or their blends with DF are reduced overall emissions (other than NOx), availability from renewable resources, and biodegradability; crankcase dilution, however, remains a concern. Methyl esters are often blended with DF. However, the poor low-temperature properties of ME are one major obstacle to such use in temperate climates. Low-temperature studies of ME-DF blends show a correlation of the low-temperature flow test and cold filter plugging point with cloud points. The low-temperature properties of methyl soyate (SME) and admixtures of methyl tallowate (TME) and SME also have been studied. Other research has dealt with preparing AE other than ME. Transesterification to biodiesel is conventionally conducted with alkaline catalysts. Now a recently developed lipase-catalyzed transesterification route to biodiesel permits the direct use of alcohols of varying structure and of feedstocks with high free fatty acid content. Using this technology, several normal and branched AE of fats, oils and restaurant grease have been prepared and their physical properties evaluated as neat esters and in blends with DF. The low-temperature properties of 20% blends of selected AE in DF are similar to neat DF.